dillstead

Extended Faneuil Hall Problem

judge = 0    
entered = 0
left = 0    
checked = 0
nojudge = Sem(1)
allsignedin = Sem(0)    
confirmed = Sem(0)
alldone = Sem(1)    

dillstead

Faneuil Hall Problem

entered = 0
nojudge = Sem(1)
confirmed = Sem(0)
checkedin = Sem(0)    
        
Immigrant thread

nojudge.wait()

dillstead

Senate Bus Problem    
        
riders = 0
mutex = Sem(1)
multiplex = Sem(50)
bus = Sem(0)
allAboard = Sem(0)

Bus thread

dillstead

Room Party Problem
    
students = 0
dean = 'not here'
mutex = Sem(1)
turn = Sem(1)
wait = Sem(0)

Dean thread
    

dillstead

// gcc -Werror -std=c11 -Wall -Wextra -Wno-error=unused-parameter -Wno-error=unused-function -Wno-error=unused-variable -Wconversion -Wno-error=sign-conversion -fsanitize=address,undefined -g3 -o unaligned_access unaligned_access.c

// Expected runtime error:
// ~/projects/tmp $ ./unaligned_access 
// unaligned_access.c:72:20: runtime error: member access within misaligned address 0x6210000010c7 for type 'struct io_data', which requires 8 byte alignment

#include <stdlib.h>
#include <sys/uio.h>
#include <stddef.h>
#include <stdint.h>

dillstead

// gcc -Werror -Wall -Wextra -D_FILE_OFFSET_BITS=64 -O2 -o read_file read_file.c
#include <stdlib.h>
#include <stddef.h>
#include <sys/stat.h>
#include <stdint.h>

int main(void)
{
    off_t file_sz = 1LL << 32;
    ptrdiff_t block_sz = 1 << 27;

dillstead

.section ".text"

	// On-board LED
#ifdef __ARM_ARCH_7A__
	// Pin 47
	mov	r1, #0x8000
#else	
	// Pin 16
        mov	r1, #0x10000
#endif

dillstead

// Find 64-bit hash collisions using a rainbow table
//
// Prints string collision pairs, one per line, until running out of
// memory or manually stopped.
//
// Porting: Implement fullwrite() and an entry point that calls worker()
// on one thread per CPU core.
//
// This is free and unencumbered software released into the public domain.

dillstead

// Refer to: https://nullprogram.com/blog/2015/05/15/
//           https://nullprogram.com/blog/2023/02/15/
//           https://nullprogram.com/blog/2023/03/23/
// gcc -Werror -std=gnu99 -Wall -Wextra -Wno-error=unused-parameter -Wno-error=unused-function -Wno-error=unused-variable -Wconversion -Wno-error=sign-conversion -fno-builtin -nostdlib -march=armv7-a -O2 -o clone_arm clone_arm.c
#include <unistd.h>
#include <stddef.h>
#include <syscall.h>

#define assert(c)   while (!(c)) __builtin_trap()
#define sizeof(x)   (ptrdiff_t) sizeof(x)

dillstead

// Refer to: https://nullprogram.com/blog/2023/03/23/
// gcc -Werror -std=gnu99 -Wall -Wextra -Wno-error=unused-parameter -Wno-error=unused-function -Wno-error=unused-variable -Wconversion -Wno-error=sign-conversion -g3 -o syscall_arm syscall_arm.c
#include <stdlib.h>
#include <stdbool.h>
#include <syscall.h>

#define countof(a)     (sizeof(a) / sizeof(*(a)))
#define lengthof(s)    (countof(s) - 1)

#define SYSCALL1(n, a) \